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A special flavor of circuit board used for high-reliability military applications. Distinguished by the fact that the outer surfaces of the board have pads but no tracks. Signal layers are only created on the inner planes, and tracks are connected to the surface pads by vias.

An area of metalization on a substrate used for probing or to connect to a via, plated through-hole, or an external interconnect.

A packaging technology in which a device's external connections are arranged as an array of conducting pads on the base of the package.

Refers to any pads, anti-pads, and thermal relief pads associated with a via or a plated through-hole as it passes through the layers forming the substrate.

Refers to a shift register in which the data is loaded in parallel and read out serially.

The effects caused by undesired resistance, capacitance, or inductance inherent in the material or topology of a track or component.

A process in which a laser beam is used to trim components such as thick-film and thin-film resistors on an otherwise unpopulated and unpowered hybrid or multichip module substrate. Probes are placed at each end of a component to monitor its value while the laser evaporates some of the material forming the component.

A technique for connecting MOS transistors such that data signals pass between their source and drain terminals. Pass-transistor logic minimizes the number of transistors required to implement a function, and is typically employed by designers of cell libraries or full-custom integrated circuits.

A type of circuit board which has conducting tracks superimposed, or "printed", on one or both sides, and may also contain internal signal layers and power and ground planes. An alternative name, Printed Wire Board (PWB), is commonly used in America.

Unit qualifier (symbol = T) representing one thousand million million, or 10¹⁵. For example, 3PHz stands for 3 x 10¹⁵ Hertz.

PGA may refer to a pad grid array or a pin grid array. A pad grid array refers to a packaging technology in which a device's external connections are arranged as an array of conducting pads on the base of the package. A pin grid array refers to a packaging technology in which a device's external connections are arranged as an array of conducting leads, or pins, on the base of the package.

An optical memory technique, in which a laser in the visible waveband is directed at a microscopic point on the surface of a slice of glass which has been doped with organic dyes or rare-earth elements. The laser excites electrons in the glass such that they change the absorption characteristics of that area of the glass and leave a band, or hole, in the absorption spectrum.

An optical memory technique, in which a laser in the visible waveband is directed at a microscopic point on the surface of a slice of glass which has been doped with organic dyes or rare-earth elements. The laser excites electrons in the glass such that they change the absorption characteristics of that area of the glass and leave a band, or hole, in the absorption spectrum.

A special transistor which converts an optical input in the form of light into an equivalent electronic signal in the form of a voltage or current.

Unit qualifier (symbol = p) representing one millionth of one millionth, or 10^-12. For example, 3pS stands for 3 x 10^-12 Seconds.

A packaging technology in which a device's external connections are arranged as an array of conducting leads, or pins, on the base of the package.

Refers to a shift register in which the data is loaded in parallel and read out serially.

Refers to a numbering system in which the value of a particular digit depends both on the digit itself and its position in the number.

A gaseous state in which the atoms or molecules are dissociated to form ions.

(1)A hole in a double-sided or multilayer board that is used to accommodate a through-hole component lead and is plated with copper. (2)An alternative name for the lead through-hole technique for populating circuit boards in which component leads are inserted into plated through-holes.

Refers to the order in which the semiconductor is doped in a MOS device. That is, which structures are constructed as P-type versus N-type material.

Refers to the order in which the semiconductor is doped in a bipolar junction transistor.

An internal layer in an integrated circuit used to create the gate electrodes of MOS transistors. In addition to forming gate electrodes, the polysilicon layer can also be used to interconnect components. There may be several polysilicon layers separated by dielectric (insulating) layers.

The act of attaching components to a substrate.

A transition from a logic 0 to a logic 1. Also known as a rising edge.

An atom or group of atoms lacking an electron.

A convention which dictates the relationship between logical values and the physical voltages used to represent them. The more positive potential is considered to represent TRUE and the more negative potential is considered to represent FALSE. Also known as positive true logic.

A process where radiation passing through the transparent areas of a mask causes previously cured resist to be degraded. The degraded areas are then removed using an appropriate solvent.

A convention which dictates the relationship between logical values and the physical voltages used to represent them. The more positive potential is considered to represent TRUE and the more negative potential is considered to represent FALSE. Also known as positive logic.

A conducting layer in or on the substrate providing power to the components. There may be several power planes separated by insulating layers.

Determines the order in which operations are performed. For example, in standard arithmetic the multiplication operator has a higher precedence than the addition operator. Thus, in the equation
6 + 2 x 3, the multiplication is performed before the addition and the result is 12. Similarly, in Boolean Algebra, the AND operator has a higher precedence than the OR operator.

Non-conducting semi-cured layers of FR4 used to separate conducting layers in a multilayer circuit board.

Simple logic functions such as BUF, NOT, AND, NAND, OR, NOR, XOR, and XNOR may be referred to as primitive logic gates or primitives.

A type of circuit board which has conducting tracks superimposed, or "printed", on one or both sides, and may also contain internal signal layers and power and ground planes. An alternative name, Printed Wire Board (PWB), is commonly used in America.

A type of circuit board which has conducting tracks superimposed, or "printed", on one or both sides, and may also contain internal signal layers and power and ground planes. An alternative name, Printed Circuit Board (PCB), is predominantly used in Europe and Asia.

A Boolean equation in which all the maxterms corresponding to the lines in the truth table for which the output is a logic 0 are combined using AND operators.

A set of literals linked by an AND operator.

A programmable logic device in which the AND array is programmable but the OR array is pre-defined.

The most user-configurable of the traditional programmable logic devices, because both the AND and OR arrays are programmable.

The generic name for a device constructed in such a way that the designer can configure, or "program" it to perform a specific function.

A programmable logic device in which the OR array is programmable but the AND array is pre-defined. Usually considered to be a memory device whose contents can be electrically programmed (once) by the designer.

A programmable logic device in which the OR array is programmable but the AND array is pre-defined. Usually considered to be a memory device whose contents can be electrically programmed (once) by the designer.

A statement that is either true or false with no ambiguity. For example, the proposition "I just tipped a bucket of burning oil into your lap," is either true or false, but there's no ambiguity about it.

A complex organic molecule formed from chains of amino acids, which are themselves formed from combinations of certain atoms, namely: carbon, hydrogen, nitrogen, oxygen, usually sulfur, and occasionally phosphorous or iron. Additionally, the chain of amino acids "folds in on itself" forming an extremely complex three-dimensional shape. Organic molecules have a number of useful properties, not the least that their structures are intrinsically "self healing" and reject contamination. Also, in addition to being extremely small, many organic molecules have excellent electronic properties. Unlike metallic conductors, they transfer energy by moving electron excitations from place to place rather than relocating entire electrons. This can result in switching speeds that are orders of magnitude faster than their semiconductor equivalents.

A form of memory based on organic proteins (see also Protein).

A form of switch based on organic proteins (see also Protein).

An artificial sequence of values that give the appearance of being random.

(1)A hole in a double-sided or multilayer board that is used to accommodate a through-hole component lead and is plated with copper. (2)An alternative name for the lead through-hole technique for populating circuit boards in which component leads are inserted into plated through-holes.

A piece of semiconductor doped with impurities that make it amenable to accepting electrons.

A type of circuit board which has conducting tracks superimposed, or "printed", on one or both sides, and may also contain internal signal layers and power and ground planes. An alternative name, Printed Circuit Board (PCB), is predominantly used in Europe and Asia.

Glossary: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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